Testing Glycerine

When treated slowly with sulphuric acid, it should not turn brown; with nitric acid and nitrate of silver, it should not become cloudy; and when rubbed between the fingers it should not emit a fatty smell.

How To Preserve Hides

Carbolic acid is used in South-America and Australia for this purpose. The immersion of hides for 24 hours in a two per cent solution of carbolic acid, and subsequently drying them, has been successfully substituted for the more tedious and expensive process of salting.

Classification Of Hydrocarbons

The classification usually adopted by distillers is as follows: All above 88° of Baume's hydrometer is called chymogene, from 88° to 70° gasoline, from 70° to 60 naphtha, from 60° to 50° benzine, from 50° to 35° kerosene, from 35° to 28° lubricating - oil.

Blue Ink

Prussian-blue 6 parts, oxalic acid 1. Mix with water to a smooth paste. Dilute with rain-water, and add a little gum-arabic to prevent spreading.

Copying Ink, Used Without A Press

Coarsely-broken extract of logwood 1 oz., carbonate of soda (crystallized) 1 drachm: heat in a porcelain capsule with 8 ozs. distilled water until the solution is of a deep-red color. Remove from fire and .stir in glycerine 1 oz., neutral chromate of potash dissolved in a little water 15 grains, and a mucilaginous solution of 2 drachms finely-pulverized gum-arabic. Keeps well, never requires a press for copying, and does not attack steel pens. The impression is taken on thin moistened copying-paper, at the back of which is placed a sheet of writing-paper.

Ink From Elderberries

Bruise the berries, place them in an earthen vessel, and keep in a warm place for 3 days. Press out and filter. Add to 12-1/2 ozs. of this filtered juice 1 oz. sulphate of iron and the same quantity of pyroligneous acid. This ink is violet at first, and afterward becomes black.

How To Restore Dim Ink

Cover the letters with solution of ferrocyanide of potassium, with the addition of diluted mineral acid (muriatic); upon the application of which the letters will change to a deep-blue color. To prevent the color from spreading, the ferrocyanide should be put on first, and the dilute acid added upon it.

White Ink For Colored Paper

1 part muriatic acid, and 20 parts starch-water. Very dilute oxalic acid may also be used. Write with a steel pen.

Imitation Ivory

To liquid chloride of zinc of 50° to 60° Baume, add 3 per cent of sal-ammoniac; then add zinc-white until the mass is of proper consistence. This cement may be run into moulds, and when hard becomes as firm as marble.

How To Make Brilliant White Light

Fill a small vessel of earthenware or metal with perfectly dry salpetre or nitre, press down a cavity into its surface, and in this cavity place a piece of phosphorus; ignite this, and the heat given off melts a sufficient quantity of the nitre to evolve oxygen enough to combine with the phosphorus, and the effect is to produce the most magnificent white light which chemistry can afford.